strange connection problems after router change

English Network/Internet
1

today updated my adsl modem/router for one with a longer wifi reach.
Since the update I have been having trouble connecting to some websites.

One such website is www.gmx.com
firefox return “server not found”.
I use an imap connection to gmx in thunderbird also and it also returns “could not connect to server”

Where it gets weird is if I fire up chromium I can connect to the gmx website but if I load Konqueror I get the server not found message.

My system is dual boot with Win7
If I boot into win7 I cannot reproduce the connection problem.

If I remove the new modem/router from the network and put the old one back in I cannot reproduce the connection problem.

Put the new modem back in and problem persists on firefox/thunderbird/konqueror only

proxy settings are the same in all programs (no proxy set).
History/cache cleared in all programs.

Anybody have any ideas?

edit: problem occurs over wireless connection and wired connection

2

I’ll try guessing.

It may be a DNS problem. Your router is likely providing a DNS server capability that does not work very well. You could use external DNS servers, instead of using your router, as a way around this – or at least you could experiment with that.

Here’s what I tried (using your example site):


dig www.gmx.com

I get back an answer with the IP address. And you probably do, too.


dig www.gmx.com AAAA

That’s a lookup for an IPv6 address.

I get back an answer with no data (i.e. no IPv6 address). And that’s fine. Presumably there is no IPv6 address. However, I have run into bad DNS services that instead give an answer NXDOMAIN (that domain does not exist). I’m guessing that is happening to you.

Properly designed software is supposed to lookup the IPv6 address first, so it will get the “server not found” (due to the NXDOMAIN). If it happens to lookup the IPv4 address first, then it will work.

As I said, those are guesses.

3

hi farcusnz

after updating to a new dsl router in June,

IPv6 had to be enabled and IPv4 had to be enabled with DHCP for good internet connections

if IPv4 was disabled only about 20% of the normal sites were available

if IPv6 was disabled only the internal network was available

also check the lease times, the default for IPv4 was 1 hour which meant a new address was looked for after 30 minutes
the setting is now set to 2 days

hth

4

Thanks
I had a play but nothing terribly insightful came up

I’ve tried your commands with the new router and the old router and the returned results are identical.

This is what I got from the new router

dig www.gmx.com

; <<>> DiG 9.9.4-rpz2.13269.14-P2 <<>> www.gmx.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7436
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4000
;; QUESTION SECTION:
;www.gmx.com.                   IN      A

;; ANSWER SECTION:
www.gmx.com.            206     IN      A       213.165.64.202

;; Query time: 36 msec
;; SERVER: 192.168.0.1#53(192.168.0.1)
;; WHEN: Thu Aug 28 13:20:28 NZST 2014
;; MSG SIZE  rcvd: 56

dig www.gmx.com AAAA

; <<>> DiG 9.9.4-rpz2.13269.14-P2 <<>> www.gmx.com AAAA
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30389
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4000
;; QUESTION SECTION:
;www.gmx.com.                   IN      AAAA

;; AUTHORITY SECTION:
gmx.com.                484     IN      SOA     dns.gmx.net. hostmaster.gmx.net. 2013071624 28800 7200 604800 600

;; Query time: 36 msec
;; SERVER: 192.168.0.1#53(192.168.0.1)
;; WHEN: Thu Aug 28 13:20:50 NZST 2014
;; MSG SIZE  rcvd: 98

What is confusing me is - if the issue is flaky DNS from the router then I should see it across all devices - but the issue is restricted to my openSUSE 13.1 install.
Win7, two android devices and a puppylinux install (and Chromium on openSUSE) do not exhibit the same issue.

tried setting google’s DNS in network manager but problem persists.

edit: one of the sites I cannot access on the new router is the openSUSE forum login page. :frowning:

5

Thanks for the suggestion
IPv6 was disabled on network manager and in the router (as it was with my old router).
enabling both hasn’t made any difference

6

Review the following

In particular, does clearing recent history help with this? Maybe the firefox IPv6 advice as well.

7

awesome - disabling IPv6 in firefox was the one that did the trick.
Not sure why it is an issue with this router and not the other but all good now.
So I also need to do this in Thunderbird - but how do I do it in Konqueror? I thought Konqueror was supposed to follow system settings? In Network Manager I have IPv6 set to “ignored”

8

For KDE apps, maybe check /etc/sysconfig/windowmanager

# To disable IPv6 support within KDE. It might solve large timeouts due to
# broken servers which claim to have IPv6 support, but do not respond.
#
KDE_USE_IPV6="no"

Not sure why NM setting isn’t enough.

9 
# To disable IPv6 support within KDE. It might solve large timeouts due to
# broken servers which claim to have IPv6 support, but do not respond.
#
KDE_USE_IPV6="no"

PS: If you do invoke that, you’ll need to restart KDE for it to take effect

10

That did the trick.
Thanks for the help. :slight_smile:

Interesting that the setting in network manager (KDE) doesn’t really make any difference when disabling IPv6.

11

Good to know. :slight_smile: